Tube bending machine



Feb. 28, 1967 F. SASSAK 3,306,093

TUBE BENDING MACHINE Filed March 9, 196

2 Sheets-Sheet l INVENTOR. FRANK SASSAK QJZM it 004% ATTORNEYS Feb. 28, 1967 F. SASSAK TUBE BENDING MACHINE 2 Sheets-Sheet 2 Filed March 9, 1964 INVENTOR.

FRANK SASSAK ATTORNiYS United States Patent ()fiice 3,3@6,d3 Patented F eb. 28, 1967 3,306,093 TUBE BENDENG MACHINE F rank Sassak, 1033 Vermont Ave., Dearborn, Mich. 48216 Filed Mar. 9, 1964, Ser. No. 350,355 2 Claims. (Cl. 72-389) The present invention relates to a tube bending machine.

It is the object of the present invention to provide an improved tube bending machine of a simple inexpensive construction capable of effectively bending tubes of different diameter and at different radii.

Heretofore, in tube bending machines the problem is to provide an effective bend in the tube without buckling. Various complicated machines have been produced for this purpose.

It is an object of the present invention to provide a novel and improved machine for tube bending.

It is another object to provide a novel form of support block with associated die block grooved to receive a tube in a horizontal position for supporting the same prior to bending within a press, together with means for reactively supporting the tube during the bending operation.

These and other objects will be seen from the following specification and claims in conjunction with the appended drawings in which:

FIG. 1 is a perspective view of the tube bending machine in inoperative position.

FIG. 2 is a perspective view of the machine in operative position applied to a press fragmentarily shown.

FIG. 3 is a longitudinal section of the machine.

FIG. 4 is a section taken in the direction of arrows 44 of FIG. 3.

FIG. 5 is a section on line 55 of FIG. 3.

FIG. 6 is a section on line 6-6 of FIG. 3.

FIG. 7 is a section on line 7-7 of FIG. 3.

It will be understood that the above drawings illustrate merely a preferred embodiment of the invention, and that other embodiments are contemplated within the scope of the claims hereafter set forth.

Referring to the drawings, the present tube bending machine, generally indicated at 11, FIG. 1, includes a pair of aligned longitudinally spaced support housings 12 and 13 adjustably securable upon the bed 14 of a press, as fragmentarily shown, employing suitable adjustable clamps 15.

Each housing includes a cylinder 16 at its outer end, and at its inner end a pair of spaced upright transversely apertured supports 17 within which are nested and secured roller bearings 18, FIG. 5.

A transverse rotary shaft 19 is journaled and supported upon and through bearings 18 in the supports 17 and is suitably retained thereon. For this purpose, upon the outer ends of each shaft 19, there is provided a transverse support block 20 adapted to cooperatively engage an exterior surface of one support 17. Removable cap 21 is mounted over the opposite end of shaft 19 and is secured relative to the opposite support 17 by a suitable fastener. A pinion 11) is positioned within the housing adjacent one of the supports and is fixedly secured to the corresponding shaft 19 by a key 9, FIG. 3.

Each cylinder 16 includes a reciprocal piston 22 sealed therein as at 23. An elongated rack gear 24 is slidably and guidably mounted within the elongated slot 25 in the corresponding housings 12 and 13, FIG. 2. Each rack gear, at one end, has an enlargement 26 secured to the respective piston as at 27. Each of the racks movably extend outwardly of the respective cylinders through elongated slot 25 in the inner end wall thereof, FIGS. 6 and 3, so as to extend under the respective shafts 19 for operative mesh with the corresponding pinions 10.

Each of said cylinders includes a head 28 at its outer end suitably secured thereto and having a passage 29 connected to the respective conduits 30, fragmentarily shown in FIG. 1, which conduits have a flexible connection therebetween, as at 32.

A source of air under pressure is delivered through pipe 33 to conduit 30 with a suitable air gauge 34 interposed for maintaining a predetermined air pressure upon the interior of each cylinder, as for example, pounds per square inch.

Each of the blocks 20 have longitudinal slots 35 therein, FIG. 4, adapted to cooperatively nest and receive a corresponding die block 36 with a suitable key 37 interposed. Suitable clamping means, such as clamp block 38, is secured as by fasteners 39 to block 20. Said clamp has an inwardly projecting grip 40 which retainingly engages the interchangeable and removable die block 36.

Each of the die blocks has across its top surface an elongated groove 41 having a radius corresponding substantially to the radius of the tube to be bent. The die blocks are interchangeable and may be replaced by similar die blocks having tube receiving grooves 41 of different radii depending upon the diameter of tube T to be bent.

When the machine is inoperative the support blocks 20 and die blocks 36 are maintained in a horizontal position to provide horizontal supports as at 41, for a horizontally disposed tube T which is positioned upon the machine for bending.

The vertically reciprocal arcuate die 42 is fixedly secured as at 43, to the vertically recirpocal platen of a press, fragmentarily shown. Said die overlies and is in substantial vertical registry with the tube T nested within slots 41 of die blocks 36. The die 42 has a radius which corresponds substantially to the radius of the bend to be formed in the tube.

The respective housings 12 and 13 which mount said die blocks are longitudinally adjustable with respect to each other and with respect to the centerline of the die depending upon the radius of bend to be made in the tube. Said housings are secured in the desired adjusted position by clamps 15, FIG. 1. In operation, the center distance between the respective shafts 19 is approximately double the radius to be formed in the tube.

As shown in FIG. 4, die 42 has an elongated groove 44 therein, of a transverse radius corresponding substantially to the radius of the tube to be bent.

Operation In operation, as the die 42 moves downwardly bending the tube, there will be a simultaneous rotary movement of the die blocks 20 away from each other with corresponding movements of the connected shafts and pinions 10. This rotary movement in unison of the two pinions upon downward compressive bending movement of die 42, causes the respective rack gears 24 to move outwardly effecting corresponding outward movement of the respective pistons 22 within cylinders 16.

As a part of the present invention, means are employed to resist this outward movement of the respective pistons. Bending of the tube under pressure is resisted by a substantially equal pressure to thus provide a better end product and to avoid buckling of the tube during bending.

As an illustration of one mechanism for accomplishing this result, a means is provided for maintaining a constant fluid pressure, such as air pressure upon the interior of the respective cylinders 16. Thus, there is a constant resistance to this outward expansive movement of said pistons during the bending operation. The constant air pressure supplied through pipe 33 is thus directed through conduits 30 to the cylinder heads at opposite ends of the cylinders for communication through passages 29 to the interior of the cylinders.

As shown in FIG. 5, the respective rack gears 24 are laterally displaced with respect to each other for guided positioning within the corresponding longitudinally aligned slots 25 formed in the respective housings 12 and 13.

In FIG. 3, with the die blocks in a horizontal position, the racks gears 24- would be retracted to their outermost positions and overlap, extending into the respective other housing in side by side engagement.

While compressed air is shown for maintaining a resistive constant pressure upon the outer ends of the respective cylinders, it is contemplated that other fluids under pressure could be employed, such as oil.

Having described my invention, reference should now be had to the following claims.

I claim:

1. In a tube bending machine characterized by an upper vertically reciprocable arcuate die and a pair of lower die blocks rotatably and adjustably secured to the bed of the machine beneath the upper die, the improved means for rotatably mounting and resisting rotary movement of each of said lower die blocks which comprises:

a housing adjustably secured to the bed of the machine,

the inner end of said housing being positioned beneath and substantially, in line with the upper reciprocable die;

said housing having a cylindrical portion formed in its outer end having a piston mounted for reciprocating movement therein;

said housing further having a rotary shaft transversely journaled at the inner end thereof;

said shaft having both a lower die block and a pinion gear fixedly mounted thereto;

a rack gear in mesh with said pinion gear and slidably mounted in said housing and secured at one end to said piston for reciprocating movement therewith;

resisting means connected with said cylinder for providing a substantially constant and uniform resistance to outward movement of said piston in said cylinder;

said die blocks adapted to support a tube to be bent in an initially horizontal position, the downward stroke of said upper die engaging the tube to be bent, continued downward movement of the upper die causing said lower die blocks and pinion gears to rotate with said transverse shaft, the rotation of said pinion gear causing outward stroking of said rack gear and piston, said outward stroking being accomplished against the continued force of said resisting means.

2. The tube bending machine of claim 1, wherein a pair of housings are horizontally mounted on the bed of the press with their inner ends adjacent to each other and with the axes of reciprocation of their respective reciprocating pistons being substantially aligned with each other.

References Cited by the Examiner UNITED STATES PATENTS 2,440,599 4/ 1948 Colwell 72389 3,021,886 2/1962 Ferris 72389 3,196,661 7/1965 Lance 72-389 CHARLES W. LANHAM, Primary Examiner.

A. L. HAVIS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,306 ,093 February 28 1967 Frank Sassak in the above identified It is certified that error appears cted as patent and that said Letters Patent are hereby corre shovm' below:

In the heading to the printed specification, lines 3 and 4, "1033 Vermont Ave., 'Dearborn, Mich. 48216" should read Dearborn Mich. (1035Vrmont Ave Detroit Mich. 48216) Signed and sealed this 5th day of August 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

1. IN A TUBE BENDING MACHINE CHARACTERIZED BY AN UPPER VERTICALLY RECIPROCABLE ARCUATE DIE AND A PAIR OF LOWER DIE BLOCKS ROTATABLY AND ADJUSTABLY SECURED TO THE BED OF THE MACHINE BENEATH THE UPPER DIE, THE IMPROVED MEANS FOR ROTATABLY MOUNTING AND RESISTING ROTARY MOVEMENT OF EACH OF SAID LOWER DIE BLOCKS WHICH COMPRISES: A HOUSING ADJUSTABLY SECURED TO THE BED OF THE MACHINE, THE INNER END OF SAID HOUSING BEING POSITIONED BENEATH AND SUBSTANTIALLY, IN LINE WITH THE UPPER RECIPROCABLE DIE; SAID HOUSING HAVING A CYLINDRICAL PORTION FORMED IN ITS OUTER END HAVING A PISTON MOUNTED FOR RECIPROCATING MOVEMENT THEREIN; SAID HOUSING FURTHER HAVING A ROTARY SHAFT TRANSVERSELY JOURNALED AT THE INNER END THEREOF; SAID SHAFT HAVING BOTH A LOWER DIE BLOCK AND A PINION GEAR FIXEDLY MOUNTED THERETO; A RACK GEAR IN MESH WITH SAID PINION GEAR AND SLIDABLY MOUNTED IN SAID HOUSING AND SECURED AT ONE END TO SAID PISTON FOR RECIPROCATING MOVEMENT THEREWITH; RESISTING MEANS CONNECTED WITH SAID CYLINDER FOR PROVIDING A SUBSTANTIALLY CONSTANT AND UNIFORM RESISTANCE TO OUTWARD MOVEMENT OF SAID PISTON IN SAID CYLINDER; SAID DIE BLOCKS ADAPTED TO SUPPORT A TUBE TO BE BENT IN AN INITIALLY HORIZONTAL POSITION, THE DOWNWARD STROKE OF SAID UPPER DIE ENGAGING THE TUBE TO BE BENT, CONTINUED DOWNWARD MOVEMENT OF THE UPPER DIE CAUSING SAID LOWER DIE BLOCKS AND PINION GEARS TO ROTATE WITH SAID TRANSVERSE SHAFT, THE ROTATION OF SAID PINION GEAR CAUSING OUTWARD STROKING OF SAID RACK GEAR AND PISTON, SAID OUTWARD STROKING BEING ACCOMPLISHED AGAINST THE CONTINUED FORCE OF SAID RESISTING MEANS. 